Hi David

The idea is that there is release agent put on the mold that the pan is formed from. This needs to be cleaned off and should be repeated if you think any oil has gotten on the pan. I personally use alcohol on a new pan first to clean off the release agent.  Oil on the pan is seen by dipping in water. Also some like to rough the pan up and take the sheen off the pan. This is not to groove the pan but just enough to take the sheen off of the surface. In the field you can take dry sand and move it around in the pan with your hand also. Hope this helps.